1. Field of the Invention
The present invention generally relates to data multiplexing, and more particularly, to methods, hardware products, and computer program products for performing high data rate wireless transmission.
2. Description of Background
In order to achieve wireless transmission of large signals exceeding one gigabit per second, Shannon's Theorem dictates that it is necessary to increase the bandwidth or raise the power per bit relative to signals which do not exceed one gigabit per second. At the same time, high frequency circuits for performing high-speed signal processing, particularly analog to digital converters (ADCs) and digital to analog converters (DACs), are generally expensive and have difficulty functioning with accuracy. Furthermore, depending on the modulation method, the impact of phase noise of the circuit configuration components cannot be ignored, making it impossible to produce effective speeds. This is particularly the case in methods for multilevel modulation of the amplitude direction. Accordingly, for the realization of high-speed high-capacity wireless transmission, a new multiplexing method that is efficient in its use of frequencies, does not create multiple values in the amplitude direction, and is resistant against circuit phase noise is needed. If these problems are resolved, it will be possible to realize a circuit configuration that can be produced at low cost.
A modulation method generally known to those of ordinary skill in the relevant art is Orthogonal MSK (OMSK). OMSK is known to be highly efficient in terms of frequency use. With reference to FIG. 1, in an orthogonally-multiplexed OMSK system 100, with the demodulation method that is generally suggested, orthogonal demodulation on the IQ plane is the base, and it is obtained on a transmitting side by preparing and mixing 4 different frequencies including a first frequency 101, a second frequency 102, a third frequency 103, and a fourth frequency 104. However, with this technique, it is necessary to provide a corresponding frequency set that includes four different frequencies on a receiving side.
In order to restore the phase rotation that arises due to the fact that the frequencies cannot be exactly the same on the transmitting side and receiving sides, it is necessary to use ADCs to perform over sampling and phase recovery. In other words, four ADCs are necessary and the circuit configuration on the receiving side becomes complex and costly. On the other hand, in the case of MSK modulation, the difference between the high frequency component and the low frequency component is exactly half the symbol rate. This fact is utilized in the configuration of FIG. 2 wherein it is possible to generate a clock signal 203 comprising a symbol rate from a received signal 201, but in such a case it is necessary to generate double the frequency, and for Gbps data rates, the impact on the circuit is large. Thus, a more simple and convenient circuit configuration is needed that can transmit and receive OMSK efficiently at high frequencies.